磁性水滑石复合材料的制备及其对曙红Y的吸附性能

Preparation of magnetic hydrotalcite composite and its Eosin Y adsorption performance

为了解决水滑石型(LDH)吸附剂在污水处理中难回收的问题,采用双滴沉淀法将磁性Fe_(3)O_(4)颗粒与具有吸附性能的Ni-Mg-Al-LDH水滑石相结合,合成了Fe_(3)O_(4)@Ni-Mg-Al-LDH磁性水滑石复合吸附材料,利用SEM、XRD、FT-IR和氮气吸附脱附等表征对Fe_(3)O_(4)@Ni-Mg-Al-LDH材料的形貌和结构进行测试,并将其用于曙红Y染料废水处理。结果表明,Fe_(3)O_(4)@Ni-Mg-Al-LDH对曙红Y染料的吸附在20 min内较为迅速,120 min后吸附趋于平衡,且随着曙红Y初始浓度的升高,Fe_(3)O_(4)@Ni-Mg-Al-LDH对曙红Y染料的吸附量也逐渐增加,最大吸附量达到108.6 mg·g^(-1)。同时,Fe_(3)O_(4)@Ni-Mg-Al-LDH对曙红Y的吸附过程符合Langmuir等温吸附模型和伪二级动力学方程,表明该吸附过程以单分子层化学吸附为主,且表面扩散和颗粒内扩散共同控制吸附速率。经五次循环后,吸附剂对曙红Y染料的去除率仍能保持80%以上,且吸附后易于磁分离,说明所制备的Fe_(3)O_(4)@Ni-Mg-Al-LDH磁性水滑石材料是一种良好的染料废水吸附剂。

In order to solve the problem of difficult recovery of hydrotalcite(LDH)adsorbent in sewage treatment,Fe_(3)O_(4)@Ni-Mg-Al-LDH magnetic hydrotalcite composite adsorption material was synthesized by combining magnetic Fe_(3)O_(4) particles with Ni-Mg-Al-LDH hydrotalcite via double-drop precipitation method.The morphology and structure of the as-prepared Fe_(3)O_(4)@Ni-Mg-Al-LDH samples were characterized by SEM,XRD,FT-IR and N_(2) adsorption-desorption technologies.And it was used as adsorbent to simulate the wastewater treatment performance of Eosin Y dye.The results show that the adsorption of Eosin Y dye on Fe_(3)O_(4)@Ni-Mg-Al-LDH is very quickly within 20 min,while the adsorption tends to balance after 120 min.In addition,with the increase of the initial concentration of Eosin Y dye,the adsorption capacity of Fe_(3)O_(4)@Ni-Mg-Al-LDH sample for Eosin Y dye increases gradually and the maximum adsorption capacity is 108.6 mg·g^(-1).Meanwhile,the adsorption process of Eosin Y dye on Fe_(3)O_(4)@Ni-Mg-Al-LDH conforms to the Langmuir isothermal model and pseudo second-order kinetic equation,indicating that the adsorption process is dominated by the chemisorption of molecular layer,and the adsorption rate is controlled by surface diffusion and intra particle diffusion.After five cycles,the removal rate of Eosin Y dye still keeps above 80%,and the adsorbent is easy to be separated by magnetic field,implying that Fe_(3)O_(4)@Ni-Mg-Al-LDH magnetic hydrotalcite composite is a good adsorbent for dye wastewater.